BLACK HOLE MASS AND SPIN FROM THE 2:3 TWIN-PEAK QPOs IN MICROQUASARS

Journal Article · Sun Jan 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/708/2/1442· OSTI ID:21392379

Mondal, Soumen ^[1]

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1. Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

In the Galactic microquasars with double peak kHz quasi-periodic oscillations (QPOs) detected in X-ray fluxes, the ratio of the twin-peak frequencies is exactly, or almost exactly 2:3. This rather strongly supports the fact that they originate a few gravitational radii away from its center due to two modes of accretion disk oscillations. Numerical investigations suggest that post-shock matter, before they settle down in a subsonic branch, execute oscillations in the neighborhood region of 'shock transition'. This shock may excite QPO mechanism. The radial and vertical epicyclic modes of oscillating matter exactly match with these twin-peak QPOs. In fully general relativistic transonic flows, we investigate that shocks may form very close to the horizon around highly spinning Kerr black holes and appear as extremum in the inviscid flows. The extreme shock location provides upper limit of QPOs and hence fixes 'lower cutoff' of the spin. We conclude that the 2:3 ratio exactly occurs for spin parameters a >= 0.87 and almost exactly, for wide range of spin parameter, for example, XTE 1550-564, and GRO 1655-40 a>0.87, GRS 1915+105 a>0.83, XTE J1650-500 a>0.78, and H 1743-322 a>0.68. We also make an effort to measure unknown mass for XTE J1650-500(9.1 approx 14.1 M{sub sun}) and H 1743-322(6.6 approx 11.3 M{sub sun}).

• OSTI ID: 21392379
• Journal Information: Astrophysical Journal, Vol. 708, Issue 2; Other Information: DOI: 10.1088/0004-637X/708/2/1442; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCRETION DISKS
BLACK HOLES
HYDRODYNAMICS
IDEAL FLOW
MASS
MATTER
OSCILLATIONS
RELATIVISTIC RANGE
SHOCK WAVES
SPIN
TRANSONIC FLOW
X RADIATION
ANGULAR MOMENTUM
ELECTROMAGNETIC RADIATION
ENERGY RANGE
FLUID FLOW
FLUID MECHANICS
INCOMPRESSIBLE FLOW
IONIZING RADIATIONS
MECHANICS
PARTICLE PROPERTIES
RADIATIONS
STEADY FLOW